The present application relates to a rotatable drum for radiology imaging modalities (e.g., imaging modalities that utilize radiation to examine an object). It finds particular application in the field of computed tomography (CT) imaging utilized in medical, security, and/or industrial applications, for example. However, it also relates to other radiology modalities where at least one of a radiation source and/or a detector array is rotated about an object under examination.
Today, CT and other radiology imaging modalities (e.g., mammography, digital radiography, single-photon emission computed tomography, etc.) are useful to provide information, or images, of interior aspects of an object under examination. Generally, the object is exposed to radiation (e.g., X-rays, gamma rays, etc.), and an image(s) is formed based upon the radiation absorbed and/or attenuated by the interior aspects of the object, or rather an amount of radiation photons that is able to pass through the object. Typically, highly dense aspects of the object (or aspects of the object having a composition comprised of higher atomic number elements in the case of duel-energy) absorb and/or attenuate more radiation than less dense aspects, and thus an aspect having a higher density (and/or high atomic number elements), such as a bone or metal, for example, will be apparent when surrounded by less dense aspects, such as muscle or clothing.
Radiology imaging modalities generally comprise, among other things, one or more radiation sources (e.g., an X-ray source, Gamma-ray source, etc.) and a detector array comprised of a plurality of pixels that are respectively configured to convert radiation that has traversed the object into signals that may be processed to produce the image(s). As an object is passed between the radiation source(s) and the detector array, radiation is absorbed/attenuated by the object, causing changes in the amount/energy of detected radiation.
In some applications, such as in security and/or industrial applications, there is a trend toward high throughput imaging. For example, a baggage inspection apparatus at an airport may be designed to image 1000 or more bags per hour (e.g., although some inspection apparatuses may be designed for to handle less bags per hour). In such applications, the radiology imaging modality is typically configured to acquire information (e.g., X-ray information) sufficient to produce the image(s) while the object under examination is being continuously translated through the examination region.
There is also a trend in some applications, such as in security and/or industrial applications, for volume imaging, where a three-dimensional (3D) image of the object is generated. It will be appreciated that a 3D image typically provides substantially more detail about the object under examination than a two-dimensional (2D) image, which may improve automatic and/or manual threat detection, for example. To generate such a 3D image, the object is typically divided into a plurality of slices and each slice is viewed from a plurality of angles, typically by rotating the radiation source(s) and/or detector array about the object as it is being examined. For example, the radiation source and/or detector array may be mounted to a rotating gantry, such as a rotating disk, for example, and the rotating gantry may be configured to rotate about the object under examination. Traditionally, the detector array and/or radiation source have been cantilevered to the rotating gantry (e.g., requiring substantial forces to be counterbalanced or otherwise accounted for).
To generate a volumetric image of an object in a high throughput environment, a large number of slices of the object are typically acquired concurrently while the rotating gantry is rotating at a relatively high speed. Therefore, the detector array must be large enough to accommodate examining numerous slices of the object concurrently. Such a detector array may be referred to as a wide-area detector array because of its large surface area in the x- and/or z-directions. The size and/or weight of such a detector poses some challenges to the traditional cantilevered design. For example, when the detector is rotating at a high speed (e.g., 150 ms per rotation), the forces of a wide-area detector array may be substantial.